Women's College Research Institute

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Unpublished research hides data on dangerous drugs

Feb. 2012

To inform their prescribing and treatment recommendations, the best doctors rely on published clinical trial data. But without the opportunity to review the unpublished data, they may not be giving their patients the best treatment.

“Only a fraction of clinical trial data – generally the positive fraction – is ever published,” says Dr. An-Wen Chan, Women’s College scientist and dermatologist, and assistant professor of medicine at the University of Toronto.

“Data that do not support the researchers’ hypothesis, or that show a drug to be ineffective or unsafe, are often left unpublished,” he explains.

This biased reporting of research leaves health-care providers with the impression that a drug is considerably safer and more effective than it actually is. The result is that “patients can be exposed to ineffective or costly treatments, or even worse, harmful ones,” says Chan.

To help give doctors more balanced information, Chan has written a guide that shows researchers how to ensure their systematic reviews capture easy-to-miss unpublished data. The guide was recently published in a special report of the British Medical Journal (BMJ)1.

Systematic literature reviews aim to provide medical professionals with a far broader and more balanced view of how a drug performs overall across multiple studies, compared to the small snapshots provided by individual studies.

“Reviews that only consider published data still don’t give doctors a reliable picture, because they’re still missing so much of the whole story,” says Chan.

Using Chan’s how-to guide, researchers can ensure their reviews provide doctors and policymakers with information that is considerably more balanced and complete.

“When doctors and policymakers have access to the full spectrum of information on a drug or therapy, including the data that’s left unpublished, it ultimately benefits patients.”

> read article

1 Chan A-W. Out of sight but not out of mind: how to search for unpublished clinical trial evidence. BMJ 2012; 344:d8013 doi:10.1136/bmj.d8013.


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